Who is Mr Buhari?

A former soldier, Mr Buhari led a military regime for 20 months in the 1980s and was first elected president in 2015, becoming the first opposition candidate to defeat an incumbent and win the presidency.
His record in office is mixed.

Mr Buhari's critics say that the very attributes that won over voters four years ago - his strictness and inflexibility - have emerged as liabilities. They accuse him of autocratic leanings as well as a disastrous tendency towards inaction.
Mr Buhari's supporters can argue that he has largely delivered on campaign pledges such as tackling corruption and cracking down on the Islamist militant group Boko Haram. But they may struggle to point to concrete achievements in other fields, such as fixing the economy.

Mr Buhari's party is compromised by senior members suspected of enriching themselves through graft. The fear is that across the board the looters will carry on pretty much as normal.

The World Bank has predicted sluggish economic growth: 2.2% for the coming year in a country with unemployment of more than 20% and nearly half the population living in extreme poverty.

President Buhari government is marred with security threats from clashes between farmers and herdsmen in the Middle Belt, continuing instability in the Niger Delta and most worrying of all, a revived threat from Islamic extremists in the northern side of the country.

the main issues?

Africa's most populous nation and largest economy faces a range of problems including power shortages, corruption, security threats, and an economic slowdown.
Nigeria is Africa's leading oil producer but corruption and a failure to invest the proceeds from the industry have hampered development.
A slow recovery from a recession in 2016 means there are not enough jobs for the large number of young people joining the employment market. About a quarter of the working age population is unemployed.

Electoral woes.

Civil society groups monitoring the election said at least 53 people were killed in political violence over the weekend.
Some 130 people have been taken into custody suspected of electoral offences, reports say.
The initial vote was postponed early on 16 February, five hours before polls were due to open.